Sterilizable probe for extraction of volatile compounds in liquids and their quantitative determination

Abstract

An improved tube probe for measuring volatile compounds in a liquid or gas contained in a reactor or in any other environment is disclosed. The probe is made of a single piece of metal, to one end of which is attached a gas permeable tubing, threaded on a supporting plate. The plate permits to use of a variety of tube lengths and diameters while protecting the tube from mechanical stress due to agitation and aeration. Furthermore, the plate gives the possibility to have a longer permeable tube than the single loop probe approach. The probe is designed so that when in use, substantially only the tube is located inside the reactor. The volatile compounds permeate into the tube into the carrier gas and the carrier gas+volatiles mixture is carried to a detector through a channel provided in the probe body. The probe is economical to make and to maintain, while achieving high performance.

What is claimed is:  
     
       1. A tubing probe for measuring a volatile compound in a fluid contained in an enclosure, comprising: 
       a probe body made of a single piece of metal;  
       inlet and outlet channels provided in the probe body;  
       a gas permeable tube attached to one end of the probe body to form a continuous passage for a carrier gas between the inlet and outlet channels;  
       a sealing mechanism between the enclosure and the probe body for isolation of inside of the enclosure, and  
       the probe body having a shoulder for positioning the probe such that the body is outside the enclosure and the gas permeable tube is inside the enclosure when the shoulder is made to rest on the exterior of the enclosure so that when the probe is inserted into the enclosure from the outside, the volatile compound pervaporates into the gas permeable tube.  
     
     
       2. The tubing probe according to  claim 1 , further comprising: 
       a supporting plate attached to the one end of the probe body for supporting the gas permeable tube.  
     
     
       3. The tubing probe according to  claim 2 , wherein the supporting plate includes a plurality of holes to which the gas permeable tube is threaded. 
     
     
       4. The tubing probe according to  claim 1 , further comprising: 
       tube adaptors attached at the one end of the probe body to which each end of the gas permeable tube is secured.  
     
     
       5. The tubing probe according to  claim 4 , further comprising: 
       the tube adaptors are larger in the outside diameter than the inside diameter of the gas permeable tube.  
     
     
       6. The tubing probe according to  claim 1 , wherein the sealing mechanism includes the shoulder on the probe body and an O-ring, so that, when inserted, a standard fermenter nut port locks the probe in place and ensures that substantially only the gas permeable tube is located inside the enclosure and at the same time sterility of the enclosure. 
     
     
       7. The tubing probe according to  claim 1 , further comprising: 
       a carrier gas supply tube connected to the inlet channel, and a volatile detector connected to the outlet channel.  
     
     
       8. The tubing probe according to  claim 7 , further comprising: 
       the probe body having a head at another end, to which head a detachable detector head-set can be attached.  
     
     
       9. The tubing probe according to  claim 1 , wherein the gas permeable tube is made of a material which is permeable to a volatile of interest. 
     
     
       10. The tubing probe according to  claim 9 , wherein the gas permeable tube has its length and diameter which are chosen to optimise the performance of the probe in relation to the volatile of interest and environment in which to operate. 
     
     
       11. The tubing probe according to  claim 9 , wherein the material of the gas permeable tube is silicone. 
     
     
       12. The tubing probe according to  claim 4 , wherein each tube adaptor is configured in two sections, the tube section to receive one end of the gas permeable tube and another section to be welded to one end of the probe body. 
     
     
       13. The tubing probe according to  claim 3 , wherein the supporting plate has a plurality of holes so that a gas permeable tube of various length and size can be threaded. 
     
     
       14. The tubing probe according to  claim 1 , wherein the probe body is designed to fit in a standard 25 mm port of the enclosure. 
     
     
       15. The tubing probe according to  claim 1 , wherein the enclosure is a bioreactor or a fermenter.